Instant photo film pack

ABSTRACT

A film pack is comprised of a case body and plural film units stacked inside the case body. An exposure opening is formed in the front wall of the film pack, and an ejection slit for advancing the film unit out of the film pack is formed in the upper wall. In the ejection slit, front and rear slit edges are confronted with each other. Engaging ridges are provided on the middle of the front slit edge. When external force is applied to the front wall, the engaging ridges press an engaged portion, which is provided in the middle of the rear slit edge. Then, the engaged portion is depressed and engaged with the engaging ridges. Thereby, it is possible to prevent further deformation of the front wall, which causes rupture of a processing fluid pod in the film unit.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an instant photo film pack thathas plural instant photo film units with processing fluid pods and acase body for containing the instant photo film units. Moreparticularly, the present invention relates to an instant photo filmpack for preventing rupture of the processing fluid pod by excessivedeformation of the case body.

[0003] b 2. Background Arts

[0004] An instant camera for use with an instant photo film pack(hereinafter referred to as film pack) is well-known. Japanese Laid-OpenPatent Application (JP-A) No. 2000-81688 discloses a film pack having abox-shaped case body and plural instant photo film units (hereinafterreferred to as film units) contained in the case. As shown in FIGS. 10and 11, the case body, comprised of a case body 11 and a rear cover 12,contains a film cover 14, a plurality of film units 15, a firstresilient plate 16 and a second resilient plate 17. All elements forcomprising the film pack are formed from plastic material havinglight-tightness. The film unit 15 includes a processing fluid pod 15 b,an exposure area 15 a and a trap portion 15 c, which are provided alongan advancing direction of the film unit 15 in this order listed. Theprocessing fluid pod 15 b contains processing fluid for developing alatent image, recorded in the exposure area 15 a, into a positive image.A surplus of processing fluid is accepted in the trap portion 15 b. Theprocessing fluid pod 15 b and the trap portion 15 c have a thicknesslarger than that of the exposure area 15 a.

[0005] An exposure opening 18 is formed through a front wall 11 a of thecase body 11, and an ejection slit 19 is formed through an upper wall 11b. The film cover 14 and plural film units 15 are stacked in a stackingdirection, and contained in the case body 11 through a rear openingformed in the rear side of the case body 11. The rear opening is coveredwith the rear cover 12. The exposure opening 18 is covered with the filmcover 14, which is ejected out of the case body through the ejectionslit 19 when the film pack is loaded in the instant camera. Afterejection of the film cover 14, the first and second resilient plates 16and 17 press the film units 15 toward the front wall 11 a, so theexposure area 15 a of the uppermost film unit 15 is appeared through theexposure opening 18. A subject image is exposed in the exposure area 15a through the exposure opening 18, and then the film unit 15 is advancedout of the instant camera through the ejection silt 19. In ejecting thefilm unit 15, the processing fluid pod 15 b is ruptured to spreadprocessing fluid over the whole exposure area 15 a, so the positiveimage is developed in a few minutes.

[0006] The ejection slit 19 has a long and narrow opening, and has asize such that the film cover 14 or the film unit 15 is able to passtherethrough. The ejection silt 19 is covered with a resilientlight-shielding flap 20 in light-tight manner. The light-shielding flap20 is partially stuck to the outer surface of the upper wall 11 b, andis partially peeled off to open the ejection slit 19 when the film unit15 is fed in the advancing direction.

[0007] As shown in FIG. 12, the ejection slit 19 has a width larger thanthe thickness of the film unit 15, so there is a possibility that two ormore film units 15 are advanced through the ejection slit 19simultaneously. In order to prevent this, JP-A No. 2000-89353 disclosesa film pack having plural guide projections 22 on an inside of a frontwall 11 a behind the ejection slit 19, as shown in FIGS. 12 and 13. Theguide projections 22 are disposed at certain intervals in the crosswisedirection. The guide projection 22 is high in the stacking directionenough to appear a top surface thereof through the ejection slit 19.Thereby, the film pack 15 is advanced without being caught by a frontslit edge 19 a. Moreover, in order to ensure to guide the film unit 15toward the ejection slit 19, each of the guide projections 22 has ataper inclined toward the front wall 11 a.

[0008] For keeping strength, the front wall 11 a is required to beformed as thick as possible. In that case, however, since the front case11 is formed from plastic material by injection molding, the front wallcan have a molding sink marks. Thus, plural grooves 11 c are formed inthe front wall 11 a for preventing molding sink marks. Between theadjacent grooves 11 c, ribs 11 d are formed.

[0009] However, the exposure opening 18 is larger than the front wall 11a, and the upper wall 11 b has a long ejection slit 19. Thus, the frontwall 11 a do not have strength enough to resist an external force. Asshown in FIG. 14, when strong external force in the stacking directionis applied to the front wall 11 a, the front wall 11 a is curved inwardsuch that the front slit edge 19 a of the ejection slit 19 comes incontact with an opposite rear slit edge 19 b. With stronger force, thefront wall 11 a is deformed such that the front slit edge 19 a islocated below the rear slit edge 19 b, as shown in FIGS. 15 and 16. Inthat case, the film units 15 is pressed by the front wall 11 a, so thelength L of the stacked film units 15 along the stacking directionbecomes small. Then, the processing fluid pod 15 b can be ruptured tospread processing fluid over the exposure area of unexposed film unit15, which is turned to be useless.

SUMMARY OF THE INVENTION

[0010] In view of the foregoing, an object of the present invention isto provide an instant photo film pack for preventing rupture of aprocessing fluid pod in an instant photo film unit, even when anexternal force is applied to a case body.

[0011] To achieve the above objects, an instant photo film pack of thepresent invention includes an exposure opening formed in a front wall ofthe film pack, an ejection slit formed in an upper wall of the filmpack, at least one engaging projection which is provided on the frontslit edge of the ejection slit and extended in the advancing direction,and an engaged portion which is provided in the rear slit edge of theejection slit. The engaging projection has a shape of a triangularprism, and is provided on the middle of the front slit edge. The engagedportion is provided in the middle of the rear slit edge. When the frontwall is deformed to close the ejection slit, the engaging projectionpresses the engaging portion. The engaged portion is depressed to beengaged with the engaging projection. Thus, it is possible to preventfurther deformation of the front wall, which causes rupture of theprocessing fluid pod in the film unit.

[0012] In order to prevent the film unit from being scratched by theengaging projection, the front slit edge has a depression in the centerwith reference to the crosswise direction of the film unit. A slope isformed in the upper wall, to project the engaged portion toward insideof the case body, and the outer corner of the engaged portion is taperedoff. On inside of the front wall behind the ejection slit, plural guideprojections for guiding the film unit toward the ejection slit arearranged at certain intervals. A gap is formed between the engagingprojection and the guide projection provided behind the engagingprojection. When the front wall is deformed excessively, the engagedportion is fit into the gap.

[0013] When the engaged portion is depressed by the engaging projection,burrs are formed in the engaged portion. In order to ensure smoothmovement of the stack of film units in the stacking direction, aregulating projection for regulating positions of the film units isprovided on inside of the upper wall. Instead of providing theregulating projection, inner corner of the engaged portion may betapered off.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and other objects and advantages of the presentinvention will become apparent from the following detailed descriptionof the preferred embodiments when read in association with theaccompanying drawings, which are given by way of illustration only andthus are not limiting the present invention. In the drawings, likereference numerals designate like or corresponding parts throughout theseveral views, and wherein:

[0015]FIG. 1 is a schematic view of a film advancing mechanism with ainstant photo film pack of the present invention;

[0016]FIG. 2 is a perspective view of the film pack of FIG. 1;

[0017]FIG. 3 is a partial sectional view of the film pack;

[0018]FIG. 4 is a rear perspective view of the film pack with partspartially broken away;

[0019]FIG. 5 is a partial sectional view of the film pack with a frontwall pressed down;

[0020]FIG. 6 is a partial sectional view of the film pack with the frontwall pressed down excessively, an edge portion being fit in a gapbetween a guide projection and an upper wall;

[0021]FIG. 7 is a partial sectional view of the film pack with burrs onthe engaged portion;

[0022]FIG. 8 is a rear perspective view of the film pack with partspartially broken away, an inner taper being formed in the engagedportion;

[0023]FIG. 9 is a rear perspective view of film pack of anotherembodiment with parts partially broken away;

[0024]FIG. 10 is an exploded perspective view of a conventional instantphoto film pack;

[0025]FIG. 11 is a sectional view of the conventional film pack of FIG.10;

[0026]FIG. 12 is a partial sectional view of the conventional film packof FIG. 10;

[0027]FIG. 13 is a rear perspective view of the conventional film packof FIG. 10 with parts partially broken away;

[0028]FIG. 14 is a partial sectional view of the conventional film packof FIG. 10 with a front wall pressed down;

[0029]FIG. 15 is a rear perspective view of the conventional film packof FIG. 10 with a front wall further pressed down, a front slit edgebeing located below a rear slit edge; and

[0030]FIG. 16 is a partial sectional view of the conventional film packof FIG. 10 with a front wall further pressed down, a front slit edgebeing located below the rear slit edge.

DETAILED DESCRIPTION OF THE EMBODIMENT

[0031] As shown in FIG. 1, a film pack 30 with an exposure opening 32 isloaded in a pack loading chamber formed in an instant camera or thelike. The pack loading chamber has an exposure frame 33 that isconfronted with the exposure opening 32 and slightly larger than theexposure opening 32. The film pack 30 has a film cover 31 for keeping aplurality of film units in light-tight fashion. After loading the filmpack 30 in the pack loading chamber, a film advancing mechanism isautomatically activated to advance the film cover 31 out of the filmpack 30 through an ejection slit 36. In response to a shutter releaseoperation, a shutter mechanism 35, provided behind a taking lens 34, isactivated to expose a latent image onto the film unit through theexposure opening 32.

[0032] The film advancing mechanism is comprised of a motor 37, a speedreduction gear train 38, a well-known claw moving mechanism 39 and aspread roller set 40. The claw moving mechanism 39 and the spread rollerset 40 are driven by the motor 37 by way of the reduction gear train 38.The claw moving mechanism 39 moves a claw member 41 inside the film pack30 through a cutout 42, for pressing a trailing end of the film unit.Then, the film unit is fed toward the spread roller set 40 through theejection slit 36.

[0033] The film unit is nipped by the spread roller set 40, and advancedout of the instant camera. In advancing the film unit, a processingfluid pod, provided in the film unit, is ruptured to spread theprocessing fluid over an exposure area, so that the latent image isdeveloped into a positive image.

[0034] As shown in FIG. 2, the film pack 30 includes a case body 44, thefilm cover 31, a plurality of film units 43, a first resilient plate 45,a second resilient plate 46 and a rear cover 47. Except the case body44, these parts are the same as those used in the conventional film unitshown in FIG. 10.

[0035] The film unit 43 is a well-known mono-sheet type, and includes aprocessing fluid pod 43 a, an exposure area 43 b and a trap portion 43c. Subject light is applied to the exposure area 43 b on aphotosensitive surface side to form a latent image. Developed positiveimage is displayed in a display area on a display surface side that isopposite to the photosensitive surface side.

[0036] A light-shielding flap 48, formed from plastic film withlight-tightness, is attached to the leading end portion of the filmcover 31. The light-shielding flap 48 is bent along the leading edgeline of the film cover 31, to form an L-shape. One end of thelight-shielding flap 48 is extended toward the film units 43 and comesin contact with an inner wall of the case body 44. Thereby, it ispossible to keep the film cover 31 from being advanced out of the filmpack 31 even when the film pack 31 is fallen down on the ground. A rearlight-shielding flap 49 for covering the cutout 42 is attached on theother end of the film cover 31, for shielding the inside of the filmpack 43 from ambient light.

[0037] In the rear cover 47 are formed two openings 47 a and 47 b, forallowing insertion of push members that are provided on a pack loadingdoor for covering the pack loading chamber. The openings 47 a and 47 bare covered with the first and second resilient plates 45 and 46 inlight-tight manner. The push members press the first and secondresilient plates 45 and 46 from outside of the film pack 31 through theopenings 47 a and 47 b. A lower portion 46 a (shown by hatched lines inFIG. 2) of the second resilient plate 46 is stuck to the first resilientplate 45. The second resilient plate 46 is bent to form V-shape whenbeing pressed by the push members. Then, the first resilient plate 45 ispressed by the upper and lower portion of the V-shaped second resilientplate 46, and presses the film units 43. Thereby, the front one ofstacked film unit 43 is pressed against the front wall 44 a, so evennessof the film unit 43 is improved. The configuration of the push membersis disclosed in U.S. Pat. No. 5,541,683.

[0038] Two supporting ridges 50 and 51 are provided on the both endportion of the rear cover 47 with reference to the crosswise direction.The supporting ridges 50 and 51 is extended in the advancing direction,and press the stack of the film units 43 toward the exposure opening 32.The processing fluid pod 43 a and the trap portion 43 c have thicknesslarger than the exposure area 43 b. Thus, the stacked film units 43 areconvexly curved toward the exposure opening 32. The supporting ridges 50and 51 are shaped in an arc, for fitting the curve of the lowermost filmunit 43.

[0039] As shown in FIG. 3, the ejection slit 36 is formed through anupper wall 44 b of the case body 44, and is covered with alight-receiving sheet 52 from outside. Two slit edges 36 a and 36 b areconfronted with each other in the ejection slit 36. A plurality of ribs44 c for compensation of strength are integrated with the front wall 44a. The ribs 44 c are extended toward crosswise direction.

[0040] As shown in FIG. 4, two regulating projections 53 a and 53 b areformed on an end portion of the rear slit edge 36 b with reference tothe crosswise direction. The regulating projections 53 a and 53 b arealso provided on the other end portion of the rear slit edge 36 b. Theregulating projections 53 a and 53 b are projected toward inside theejection slit 36, which causes the ejection slit 36 partially narrower.Thereby, it is possible to prevent ejection of two or more film units36. In order to prevent a scratch on the display surface of the filmunit 43 and pass the light-shielding flap 48, the regulating projections53 a and 53 b are not provided on the middle of the rear slit edge 36 b.

[0041] In the middle of the front slit edge 36 a is formed a depression36 c, on which two engaging ridges 54 are provided at a certaininterval. The engaging ridges 54 have shapes of triangular prism oneside of which is united with the depression 36 c. The engaging ridges 54are extended in the advancing direction, so the engaging ridges 54 andthe rear slit edge 36 b are crossed. The engaging ridges 54 areprotruded toward the ejection slit 36, but not beyond the level of thefront slit edge 36 a for preventing scratch to the exposure area 43 b.As shown in FIG. 5, when the front wall 44 a is pressed down by externalforce, the engaging ridges 54 come in contact with the rear slit edge 36b.

[0042] In FIG. 4, in the upper wall 44 b is formed a slope 55, which isinclined toward the rear slit edge 36 b and projected slightly towardinside of the case body 44. The slope 55 becomes thinner as it extendstoward the rear slit edge 36 b. Moreover, outer corner is chipped tohave a taper 56 in the middle of the rear slit edge 36 b, so that anengaged portion 60, the area confronted with the engaging ridges 54,becomes sharp pointed. When the front wall 44 a is pressed down, theengaged portion 60 is pressed against the engaging ridges 54. Since theengaging ridges 54 are extended in the direction perpendicular to theengaged portion 60, the engaged portion 60 is partially hollowed by theengaging ridges 54 without being slid upward or downward. Thereby, it ispossible to prevent excessive deformation of the front wall 44 a, whichcauses rupture of the processing fluid pod 43 a.

[0043] The engaged portion 60 has a thin tip and is projected downwardslightly. Thus, when external force is applied to the front wall 44 a inthe state where the engaging ridges 54 are engaged with the engagedportion 60, the upper wall 44 b is convexly curved toward the inside ofthe case body 44.

[0044] The guide projection sets 57 and 58 are provided on an inside ofthe front wall 44 a behind the ejection slit 36, as described in theprior art section. The guide projection set 57 is provided below theengaging ridges 54. Each of the guide projection sets 57, 58 iscomprised of two projections arranged at a certain interval. The centerguide projection set 57 is shorter than the other guide projection set58, so there is a gap 59 between the engaging ridges 54 and the guideprojection set 57. When the front wall 44 a is pressed down by strongerexternal force, the engaged portion 60 is slipped to insert into thecase body 44. Then, the engaged portion 60 is fit inside the gap 59, forlocking the rear slit edge 36 b, as shown in FIG. 6. Thereby, the rearslit edge 36 b is not deformed any more, so the length of the stackedfilm units 43 in the stacking direction is kept at a certain value.Accordingly, it is possible to prevent rupture of the processing fluidpod 43 a. In order to keep the rear edge 36 b from deformation, it ispossible to form a groove or a cutout in an inside of the front wall 44a, instead of the gap 59.

[0045] The engaged portion 60 is depressed to have a burr 62 (see FIG.7) when being pressed by the engaging ridges 54. The burr 62 isprojected toward inside of the case body 44, so there is a possibilitythat the stacked film units 34 are caught by the burr 62, to preventsmooth movement of the stacked film units 34 in the stacking direction.In order to prevent this, regulating projections 61 are provided on theinside of the upper wall 44 b, as shown in FIGS. 4 and 7. The regulatingprojections 61 are extended in the stacking direction, and is projectedtoward inside of the pack case 44. Stack of the film units 43 areregulated their positions by the regulating projections 61 inmanufacture. The regulating projections 61 are much higher than the burr62, so it is possible to keep smooth movement even when the engagedportion 60 is depressed to have the burr 62.

[0046] Instead of the regulating projections, an another taper 62 may beprovided in an inner corner of the rear slit edge 36 b, as shown in FIG.8. Since the burr is not projected beyond the inner upper wall 36 b,stack of the film units 43 are not caught by the burr.

[0047] In the above embodiments, the engaging ridges 54 are provided onthe front slit edge 36 a, and the engaging portion 60 is provided in therear slit edge 36 b. To the contrary, as shown in FIG. 9, engagingridges 64 may be provided on the front slit edge 36 a. In that case, adepression 63 is formed in the middle of the rear slit edge 36 b forpreventing the film unit 43 from being scratched by the engaging ridges64. When external force is applied to the front wall 44 a, the engagingridges 64 are pressed onto an engaged portion 65 provided in the middleof the front slit edge 36 a. In addition, a taper 65 may be formed inthe inner corner of the front flit edge 36 a, in the same way as thefirst embodiment.

[0048] In the above embodiments, the film pack 30 is used for an instantcamera, but the film pack of the present invention is applicable to aprinter or the like. Moreover, a transfer-type film unit, in which theimage display surface is opposite to the photosensitive surface, is usedin the above embodiment, but the present invention is also applicable toa reflection-type film unit in which the photosensitive surface is thesame as the image display surface.

[0049] Thus, the present invention is not to be limited to the aboveembodiments, but on the contrary, various modifications are possible tothose skilled in the art without departing from the scope of claimsappended hereto.

What is claimed is:
 1. An instant photo film pack having a plurality ofinstant photo film units and a case body for containing said instantphoto film units stacked in a stacking direction, an exposure openingfor taking an exposure to said instant photo film unit being formed in afirst wall of said case body, an ejection slit for advancing saidinstant photo film unit out of said instant photo film pack being formedin a second wall perpendicular to said first wall, said ejection slitbeing extended in a crosswise direction of said instant photo film unitand having a first slit edge and a second slit edge which are confrontedwith each other, said film pack comprising: at least one engagingprojection provided on said first slit edge, said slit edge beingextended in an advancing direction of said instant photo film unit,which is perpendicular to said crosswise direction; and an engagedportion provided in said second slit edge, said engaging projectionbeing engaged with said engaged portion when said first wall is deformedto close said ejection slit, for preventing further deformation of saidfirst wall.
 2. A film pack as claimed in claim 1 , wherein said engagingprojection is provided on the middle of said first silt edge, and saidengaged portion is provided in the middle of said second slit edge.
 3. Afilm pack as claimed in claim 2 , wherein said engaging projection has ashape of a triangular prism, one side of said triangular prism beingunited with said first silt edge.
 4. A film pack as claimed in claim 3 ,wherein said first slit edge is located in a side of said first wall. 5.A film pack as claimed in claim 4 , further comprising: a first guideprojection provided on said first wall behind said ejection slit, saidfirst guide projection being extended in said advancing direction andguiding said instant photo film unit toward said ejection slit.
 6. Afilm pack as claimed in claim 5 , wherein said first slit edge has adepression in the center with reference to said crosswise direction,said engaging projection being provided on said depression.
 7. A filmpack as claimed in claim 6 , wherein the outer corner of said engagedportion is tapered off.
 8. A film pack as claimed in claim 7 , whereinsaid second wall has a slope inclined toward inside of said case body,said second slit edge being projected toward inside of said case body,and said engaged portion being provided in the tip of said slope.
 9. Afilm pack as claimed in claim 8 , further comprising: a second guideprojection extended in said advancing direction, said second guideprojection being provided on said first wall behind said engagingprojection, said second guide projection guiding said instant photo filmunit toward said ejection slit; and a gap being provided between saidsecond guide projection and said ejection slit, said engaged portionbeing fit into said gap when said first wall is deformed excessively.10. A film pack as claimed in claim 9 , further comprising: a thirdguide projection provided on inside of said second wall, said thirdguide guiding movement of stacked said film units in said stackingdirection.
 11. A film pack as claimed in claim 9 , wherein the innercorner of said engaged portion is tapered off.
 12. A film pack asclaimed in claim 3 , wherein said second slit edge is located in a sideof said first wall.
 13. A film pack as claimed in claim 12 , furthercomprising: a guide projection provided on said first wall behind saidejection slit, said guide projection being extended in said advancingdirection, said guide projection guiding said instant photo film towardsaid ejection slit.
 14. A film pack as claimed in claim 13 , whereinsaid first slit edge has a depression in the center with reference tosaid crosswise direction, said engaging projection being provided onsaid depression.
 15. A film pack as claimed in claim 14 , wherein theinner corner of said engaged portion is tapered off.